MOLD FOR MOLDING SUBSTRATE OF OPTICAL RECORDING MEDIUM AND MOLDING MACHINE

摘要

PROBLEM TO BE SOLVED: To manufacture an optical disc substrate which has no sink mark in inside peripheral thick part and less double refraction when a thin optical disk substrate where the plate thickness of the inside peripheral part is larger than that of an information recording area, by an injection molding method. SOLUTION: A mold 1 is composed of a fixed die la and a moving die 1b, a recess 31 is formed on the compressed surface of the moving die 1b so that the substrate of an optical recording medium where the plate thickness of the inside perimeter is larger than that of an information recording area and the plate thickness of the information recording area is constant may be molded from a resin material. Within the moving die 1b, there are a piston 8 and cylinder 9 which compress only a resin material part forming the inside perimeter from the information recording area of the substrate.